Center for Advanced Study & Research on Intellectual Property


CASRIP Newsletter - Summer 2008, Volume 15, Issue 2

How to Draft American Style Patent Claims

by Kanji Fujiyoshi[1]


A. Features of Patent English:Patent English is a composite of Technical and Legal English
B. Sections in an American Patent Specification and Where Legal Weight is Found
C. What is “Reciting in Phrase”?
D. Root Directive Formula for Claim Drafting
E. Examples of Claims for Simple Products
F. Basics of Means Plus Function Claims
G. Topics Related to Patent Translation Business

This article is designed to guide beginners in non-native English speaking countries the art of how to draft American style patent claims. First, the article will emphasize some features of English typically used in claim drafting, writing in phrase, for example. Next, the article will introduce the root directive formula and provide examples for its application. Then, the article will relate the basic concept of means plus function claims. It will conclude with some topics related to the patent translation business in Japan.[2]

A. Features of Patent English:Patent English is a composite of Technical and Legal English

More precisely mentioned, Patent English = (1) Technical English + (2) Legal Consideration + (3) Unique Technique. Both technical and legal English, (1), are unemotional and written in condensed wording.

Legal consideration, (2), does not use the same style of writing. Some examples demonstrating legal consideration are:

(a) Words that are likely related to a claim should be mentioned in singular or mentioned so as to include a singular case, such as “at least one.”

(b) Mentioning a range should be noted using “from and to” instead of using “between” (for example, temperatures from 0℃ to 100℃).

Some examples of unique technique, (3), are:

(a) It is a widely accepted grammatical rule that if a noun is appended with a number or character such as 1, 2, or A, that is, claim 1, page 1, point A, World War II, any article (a, an, the) is omitted from the front of the noun. This is the “no article rule.” In patent English there is an exception, however. When a noun is the name of a part shown in a drawing appended to specification, for example, “a lever 1” shown in Fig. 1, where the indefinite article “a” indicates the first occurrence of the lever, then “a lever 1” is accepted. Thus, the “no article rule” is not applied if “lever” comes from a drawing.

(b) If a cylinder is cut obliquely, the section should be an ellipse, but in patent English, it is called an “ellipsoid,” instead of an “ellipse” to be slightly vague and to potentially encompass a broader meaning.

B. Sections in an American Patent Specification and Where Legal Weight is Found

(a) Title of the Invention

(b) Background of the Invention: (b-1) Field of the Invention, (b-2) Description of the Related Art.

(c) Summary of the Invention

(d) Brief Description of the Drawings

(e) Detailed Description of the Preferred Embodiments

(f) Claims

In the above sections, (f) Claims use legal English with a unique format. In contrast, section (e) Embodiments use technical English. As a result, in the case of the first occurrence of “a radius of a circle,” it will be written “the radius of a circle” in Embodiments according to the technical sense, but in (f), it will be “a radius of a circle” according to the legal sense. The unique English in a patent claim favors the use of an indefinite article. The same is true with “the thickness of a film” (in an embodiment) in contrast to “a thickness of a film” (in a claim).

C. What is 'Reciting in Phrase'?

A claim is formatted as “I/We claim: (X)” or “What is claimed is: (X),” this is called the “one sentence rule.” Thereby (X) is “one term” in this sentence. However, X will be replaced in claim 1, claim 2, claim 3, and so on, by internally developed content. Therefore, X is a constituent of the “one sentence rule” and at the same time stands for each claim. Each claim has content comparable to one sentence, but the term “one sentence rule” has not arisen from mentioning the content of each claim. The recitation of a claim is normally expressed by terms and phrases in place of sentences. Thus, “reciting in phrase or sentence fragment” is thought to show a subsidiary relationship to the foregoing “one sentence.” It is said that this unique format comes from Common Law practice.

When “What is claimed is” format is chosen (this format will be considered in the following), (X) is a complement in our grammatical knowledge, but this term is recognized to be the object by Americans.[3] There is a gap. We Japanese were taught to use the sentence structure, S+V+O+C in English. For example, “I saw him running.” It is my understanding that such an analysis as S+V+O+C has been used in England, but not in America. Such information may be helpful for us to understand the gap between American and English people's style of writing patent claims.

Based on such general considerations, Japanese should familiarize themselves with recitation in phrase. For example: One end of the lever is fixed to the shaft.→The lever has one end fixed to the shaft.→The lever having one end fixed to the shaft. In addition, the word “having” is disfavored in technical English (“with” is employed), but it is favored in patent English. It is said that the use of “having” in patent English comes from legal English. For example, a corporation having its principal office at… .

*** Other Examples of Conversion from Sentence to Phrase ***

  (Sentence) → (Phrase)

(1) I have a book → My having a book

(2) I went to Tokyo by Shinkansen → My having gone to Tokyo by Shinkansen.

(3) He knows that I have this book. → His knowing my possession of (or my having) this book.

The wording “Fig. 1 shows” has been disliked by American attorneys in describing a patent specification because the verb “show” means “prove” in the legal sense. Therefore, should some error be found later in Fig. 1, after the grant of the patent, and should such point be availed by an opponent in a later lawsuit, the opponent would argue that what “Fig. 1 shows or proves” is false. Consequently, to escape from this potential harm, American attorneys have employed “illustrate” or “represent,” in place of “show.”

Legal terms or words are often used in a “singular-with-no-article” form, such as “service of process.” This usage is likened to the usage of a headword or an entry word in a dictionary. Taking “matter” as an example, “matter” such as “matter of right” is a general expression, and “a matter of right,” “the matter of right,” “matters of right,” or “the matters of right,” are also allowable.

Singular Plural

Indefinite a matter matters Definite the matter the matters

Similarly, the “singular-with-no-article” form of “means” as a legal word represents “a means,” “the means provided with singular meaning,” “means provided with plural meaning,” and “the means provided with plural meaning.”

Singular Plural

Indefinite a first means enumerated means

Definite the first means the enumerated means

Technical English allows “a means of transferring information” in its usage. “A” is applied and “of” is used, in place of “for” in patent English. As an aside, “means for” in a claim body usually leads to the development of a functional expression such as “means for achieving a specified function.” So, this is useful phraseology in claim drafting. However, patent English notes in comparison with technical English: means for transferring information. There is no article in the front of “means” like the headword as noted above.

Furthermore, it is likely that American examiners use “applicant” in the “singular with no article” in Office Actions is because the Code for Federal Regulations (CFR) § 1.41 notes “applicant” the same as “singular with no article.”

*** Summary of Rules for using the article (a, an, the) in drafting a specification including a claim ***

The American Examiner's control is strict on the usage of the article (a, an, the) when it comes to claim drafting, but is not strict when it comes to a description in a specification body. Generally, the Examiner does not include grammatical errors in the Office Action as far as such have been found outside of a claim. The following are the rules applied not only to the claims, but also to the specification body.

Rule 1. The same as school grammar, that is, the indefinite article (a, an) is put before a noun at its first occurrence. In subsequent occurrences use the definite article (the).

Rule 2. No article is put when a noun is appended with a number or a character in order to express limitation such as: claim 1, page 1, line 1, circle A, World War II, rendering it a proper noun.

Rule 3. If the number or character is added to indicate a part of a product in a drawing as a “legend” where such numbering anticipates the naming of such part, it deserves the reverse of rule 2. When a legend number has preempted the naming to be used in describing a specification, the article is revived in such a manner as “a lever 1,” “a plate 1.”

Rule 4. No article is used when a noun acts as a headword such as “SUMMARY OF THE INVENTION.” Legal terms or words are often used in “singular-with-no-article” form.

Rule 5. In drafting an embodiment example where technical sense governs, “the radius of a circle” is used at the first occurrence, but in drafting a claim where legal sense governs, the first occurrence is: “a radius of a circle.” The same is true in the case of “thickness of film” as below: “the thickness of a film” in the technical sense, and “a thickness of a film” in the legal sense.

D. Root Directive Formula for Claim Drafting

In this section, the equation for the definition of a term, that is, Definition of a Term = Class or Genus + Differentia is introduced as indicating “the root directive formula” for drafting a claim or mirroring the basic structure of a claim. In this connection, a few dictionaries will be cited, and in specific examples, such as in the definition of “steam engine,” there will be indicated how the terms used in the definition correspond to the preamble, the transition, and the claim’s body.

“Definition of a term” is explained in the online dictionary ONE LOOK as follows:

A genus-differentia definition is one in which a word or concept that indicates a species -- a specific type of item, not necessarily a biological category -- is described first by a broader category, the genus, then distinguished from other items in that category by differentia. The differentia of a species is the species' properties that other members of the genus do not have. In short, the genus is the broad category, the species is a type within that category, and the differentia is the distinguishing characteristics of the species.

*** Illustration from ONE LOOK (1) ***

Let us look up the quick definition given for “steam engine” by ONE LOOK.

It reads:

Noun: “external-combustion engine in which heat is used to raise steam which either turns a turbine or forces a piston to move up and down in a cylinder.”  

In the above (1), “external-combustion engine” is cited as a term superordinate from the subject term “steam engine,” that is, the first step lies in enlarging the subject term, which in concept embraces the subject term therein. This indicates the preamble in claim drafting. Then, the next words “in which” indicate the “transition.” “Heat is used…” indicates the “claim body.”

*** Another Dictionary (2)  ***

“An 'engine' 'that' 'converts' the heat energy of pressurized steam into mechanical energy, especially one in which steam drives a piston in a closed cylinder.”

In this example, the “preamble” is “engine,” “that” is the “'transition,” and “converts…” is the “claim body.”

The first step in the process of drafting lies in enlarging the subject matter in concept to create a superordinate concept as the preamble and then limiting the preamble so as to depict features of the subject matter and to distinguish it from prior art (formation of differentia). So, this second step will always proceed with limitations from the superordinate concept to the subordinate concept. However, in this contribution, the efforts of distinguishing the subject matter from the prior art will not be included.

*** Summary of Reciting in Phrase ***

(1) Recite in phrase completely or do not use any sentence.

Do not recite “a wherein sentence clause” in an independent claim, because it will be equivalent to “a dependent claim,” which would be interpreted in a narrow scope. It is highly regrettable that professional patent translators in Japan dislike “the reciting in phrase” technique and tend to use the “wherein sentence clause,” thereby creating equivalents to dependent claims in an independent claim instead of broadening the claim scope. Sometimes, Japanese translators will subconsciously convert a claim-to-be-drafted into a “Jepsom type” claim as a result.

(2) Do not use the relative pronoun “which.”

Because “which” is unsuitable for “the reciting in phrase” method, the antecedent language should be repeated, in place of “which.”

(3) Use “upon” to create a conditional recitation, in place of “when,” “if” or “in the case of.” For example, “upon the monitor system receiving a response signal from the end effector.” These three conditions were taught to Japanese trainees in claim drafting lessons about 20 to 30 years ago by American patent law firms. During the past 20 years, the number of people who engage in patent translation has largely increased in Japan. However, most of the translators have not received the lessons in or from an American law firm. Moreover, native English speakers have come to Japan featuring the advantage of an “English native” quality as a sales point and have entered the same patent translation business. However, it is wondered whether such newcomers have previously received training in the art of patent claim drafting from any American patent attorney. Accordingly, nowadays the three conditions noted above are not always followed. This contributor still believes in the advisability of these three conditions, however.

E. Few Examples of Claims of Simple Products

Example 1. Carton Box. As for drawing thereof, refer to Appendix, below. 

Preparation for Drafting

1. Finding a preamble, that is, a superordinate term which embraces a carton box in concept should be proposed. Such as: a paper-made cubic vessel; a paper-made article for providing a cubic space; a paper-made container providing a cubic space.

2. Proceeding with limitations to depict features of the subject carton box from a broader (higher ranked) concept to a narrower (or lower ranked) concept. Important elements: square shape, upper opening, and turnable flaps.

3. Finished Sample claim

The first instance.

A paper-made article for providing a cubic space, comprising:

(a) the cubic space including configuration by four side planes and one bottom plane having continuity with each other;

(b) the cubic space also defining an upper opening by four peripheries made of the side planes;

(c) each of the upper peripheries being provided integrally with a turnable flap to close the upper opening.

The second instance.

A paper-made article providing for a cubic space, comprising:

(a) a square flat bottom continued to four upstanding side walls having side by side connection;

(b) upper edges of the side walls defining a square opening at a position upward from and parallel to the bottom;

(c) a swingable flap on each of the upper edges, whereby the flaps enclose the opening upon being swung inward.

Example 2. Scissors

A cutting tool by hand comprising:

1. a pair of metal blades each having a blade portion and continuing to a non-bladed extension, said pair being combined with a pivot located between the blade portion and the non-bladed extension;

2. said pair of the blade portions providing for turning across (*) each other to slide in close association;

3. each non-bladed extension having an end provided with a lobe ring for a finger to be inserted.

(*) claw action in other words.

Example 3 Chair

What is claimed is: (又は I/We claim)

An article for house interior comprising:

1. a generally round, flat plate having an upper side and a lower side;

2. four supports attached to the lower side for self-standing with the flat plate kept horizontal;

3. a bowed wall mounted upward on the upper side for defining a portional circumference around the flat plate at an appropriate height.

Dependent claim from claim 1

The article defined as claim 1 being further provided with (comprising) a soft material padded inside a cover of the upper side.

*** Now Let Us Try to compose the example 3, chair claim, according to the root directive formula ***

Please assume that a drafter is going to work on this task according to the root directive formula. The first step is to imagine or create a superordinate term that embraces the goal product, chair. It may be “an article for house interior” or “a furniture module.” The next step is to detail or mention three parts that constitute the goal product, that is, seat (flat plate), legs (supports), and seat back (bowed wall). Each of these three parts is recited in an individual clause to mention each part as well as to depict which structural relationship is provided with the mentioned part in cooperation with other part or parts in a framework as chair (it is otherwise called “specified function” as shown below). For instance, four supports (mentioning which part) for self-standing with the flat plate kept horizontal (structural relationship with a different part or function, by patent terminology).

In this example, the phrase writing is employed to conform to a typical style: a claim element for performing a specified function. Then, to finalize, the claim element reads: “four legs attached to the lower side of the flat plate.” The next, “for self-standing” reads “for performing.” The following reads the function, that is, “with the flat plate kept horizontal.”

The preposition “for” is used three times in this example. In the first time, it is used in the preamble to indicate “usage,” and in the second and in the third times it is used in the claim body or in the clause. This “for” indicates a function to be performed by the element. So, in this case the recitation format follows a typical “element and its function.”

Further, the clause (1) reads: a generally round, flat plate having an upper side and a lower side, that is, it does not stop at “flat plate,” and it includes “having an upper side and a lower side.” These extension terms are significant in creating an interrelationship with the other two parts (2), and (3).

*** Process Claim with use of Providing Step ***

Some inventive patent publications suggest that the process involved will proceed under the control of mechanics or hardware. In such situation, a feeling that it will be difficult to file a process claim on that topic may arise. In this case, a process claim using the “providing step” would be utilized. Drafting process claims using “providing step” is not inherent in Japan. So, the Japanese way of drafting a process claim may be as follows: A process for performing a particular function “using” a machine which includes: (mechanical recitation ensues); said process comprising the steps of: (process recitation ensues).

In essence, the recitation of the machine and the process is repeated, connecting the two. However, introduction of the “providing step” makes the recitation easier as will be shown in the following example concerning the process for preparing a simple soup.

Process of preparing soup comprising the steps of:

1. providing cooking means, said means including pan, stirrer, cup, and soup premix cake;

2. pouring a quantity of water into the pan;

3. heating the water up to a boiling temperature;

4. charging the soup premix cake into the boiling water;

5. stirring the boiling water with the stirrer and allowing same to stand;

6. distributing a hot soup into cups.

Another example can be taken from the United States patent US4607483, which relates to a machine for twisting material fiber bundles and stretching them into rope product, with a process claim added.

“A method of advancing and twisting a plurality of generally parallel, endless strands into a rope configuration comprising the steps of:

(A) providing a conveyor means having at least two side walls, one side wall defining a series of side-by-side rollers, skewing a rotational axis of each roller to a predetermined angular position relative to horizontal and vertical planes, rotating the rollers in unison about their axes in a predetermined direction,

(B) feeding said strands into said conveyor means and into frictional contact with sand rollers,

(C) whereby the rollers by virtue of their skewed disposition and direction of rotation are effective to develop two force components, one component operating to twist the strands into rope while the other component operates to advance the twisted strands through the conveyor means.”

In the above recitation, a process is only affected by clause (B). As for the drawing in US4607483, refer to the Appendix below.

F. Basics of Means Plus Function Claim

Following is a famous claim example with “SHAKER” shown in the book by Landis.[4] The discussion starts with the fact that “means clause” is employed only by one clause (d) while the others (a), (b), and (c) are otherwise. It shows that the “means clause” was employed only in the unessential component or power supply means. It means that when this example was created, the use of the “means clause” stayed only in the unessential region of the invention. However, the employment of “means clause” expanded while the present Patent Law section 112 was not yet drafted. In 1946, the famous Halliburton[5] decision was issued, and, in its wake, the present section 112 was enacted in 1952. If the enactment of this statute is likened to be the birth of Jesus Christ, Landis's example is the product from the B.C. age, and the contributor's example, which employs all two “means clause,” shown below, is likened to a product in the A.D. age.

In this connection, MPEP 2173.05(g) is cited as showing a fundamental feature of the means plus function claim in the clearest and easiest way.

*** Citation of the First Paragraph of MPEP2173.05(g) ***

2173.05(g) Functional Limitations [R-3]

A functional limitation is an attempt to define something by what it does, rather than by what it is (e.g., as evidenced by its specific structure or specific ingredients). There is nothing inherently wrong with defining some part of an invention in functional terms. Functional language does not, in and of itself, render a claim improper.[6]

*** From Page 17, Landis(2nd ed.)***


“Apparatus for shaking articles,

which comprises:

(a) a container for the articles:

(b) a base;

(c) a plurality of legs;

each of which is connected pivotally at one end to the container and at the other end to the base, to support the container for oscillating movement with respect to the base, and

(d) means for oscillating the container on the legs to shake the articles.”

*** Shaker Claim Including Two Means Clauses ***

“Apparatus for shaking articles, comprising:

a first means for holding the articles stored in a container, including the container at an upward position, a base at a substrate position, a plurality of support legs connected endwise to the container and a flexible means mounted on the base, and said flexible means including pivots and coil springs;

a second means for empowering reciprocating movements to the first means, including a motor and a rotatable shaft followed by a power train having an eccentric cam and a press rod held by the first mean to keep the container reclining on the cam during the reciprocating movements.”

(A term 'flex means' is created including 'pivot' and 'coil spring')

The drawing 'APPENDIX A' is cited from Page 219, Mechanics of Patent Claim Drafting, 2nd ed. Published by PLI. As for the drawing (APPENDIX A, Example I - SHAKER), Refer to the Appendix below.

Today the use of the means plus function (M&F) recitation is not so popular among clients as in the past, but the M&F style has definite merit in some aspects. So this contributor proposes the use of it in the BC age manner in the Shaker case, that is, the approach by the M&F should be limited to a clause for the conventional art in a claim that would not contain the novelty point.

*** Comparison between Section 101 and 112.6 (M&F) from the view point of the language used in these sections ***

Section 101 reads:

“Whomever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title”.

Section 112.6 reads:

“An element in a claim for combination may be expressed as 'a means' or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.”

Section 101 is the broadest section providing the four categories: process, machine, manufacture, and composition of matter. Close observation on these two sections teaches that the language for each category in S.101 is reduced to a narrower language in S.112.6 which is likened to the preamble in a claim vs. a clause in a claim as shown below:


machine, manufacture→structure

composition of matter→material


(Words in S.101→Words in S.112.6)

Why is subordinate language used in section 112.6? It is because section 112.6 stipulates the level of elements involved in a claim, instead of a claim as a whole. So, the term with an indefinite article, “a means,” one of case variables, subordinate of “means (singular-with-no-article)” is employed.

G. Topics Related to the Patent Translation Business in Japan

The patent translation business in Japan has been expanding like the budding out of bean sprouts after a rain. Many English conversation schools are making efforts to convert themselves to or shifting focus to the patent translation business. In addition, a new business entry is also found. TORAY, a reputable corporation in the field of plastic, film and chemical manufacture, has started a new patent translation school planning to teach soon retiring engineers. Their project is reportedly successful.

However, the difficulty lies in the shortage of good teachers. This contributor claims that, in such schools or seminar classes, they should teach English, taking into consideration that patent English has two aspects of technical and legal sense as noted. For instance,


(1a) Air 'contains' nitrogen four times the amount of oxygen.

Only (1a) does not meet this contributor's claim. There the second one (1b, below), for instance, should be added in Japanese patent English classes:

(1b) Air 'is inclusive of' nitrogen four times the amount of oxygen.

One more example is that:


[2a] The car 'ran' 10 km with power off.

[2b] The car 'was on the run' 10 km with power off.

However, satisfactory news has not yet reached this contributor.

Any comments will be welcome.

   This contributor's Email address:


Carton Box

Carton Box

Drawing in USP 4607483

Drawing in USP 4607483





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  • [1] Mr. Fujiyoshi is a patent attorney with the Fujji Patent Firm in Japan.
  • [2] i In the translation business, there are famous books by John L. Landis (Robert C. Faber, Landis on Mechanics of Patent Claim Drafting (5th ed. 2007)) and Jeffery G. Sheldon (Jeffery G. Sheldon, How to Write a Patent Application (1992)), utilized by many translators in Japan and other Asian countries. However, most translators are behind in studying the art of patent translation. This article is intended to provide a quick reference.
  • [3] ii See Manuel of Patent Examining Procedure (MPEP) § 608.01(m).
  • [4] John L. Landis, Mechanics of Patent Claim Drafting 17 (2d ed. 1974). Note that the Landis book is now in its fifth edition.
  • [5] Halliburton Oil Well Cementing, Co. v. Walker, 329 U.S. 1 (1946).
  • [6] See In re Swinehart, 439 F.2d 210, 169 USPQ 226 (CCPA 1971).

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Last updated 4/27/2012